Microfiche and reader

ABSTRACT

A microfiche having one surface embossed or molded to define a multiplicity of small lenses (lensettes) integral with the microfiche. Each micro-image is stored directly below a corresponding lensette, thereby assuring optical distance registry between each micro-image and its projection. Lateral optical registry is also realized. In an embodiment, interlensette surface of the microfiche is made opaque to preclude optical cross-talk.

This is a division of application Ser. No. 309,968, filed Nov. 28, 1972,now U.S. Pat. No. 3,864,034 filed Feb. 4, 1975.

This invention relates to a distributed optical information storage andretrieval system. It more particularly relates to a novel method forpositioning the intelligence on a microfiche with respect to lenses forprojecting the intelligence on a viewing screen.

In certain prior constructions of micro-optic readers, (such asdescribed in copending application Ser. No. 135,996, filed Apr. 2, 1971by Adnan Waly for "Micro Image Recording And Read Out System," andassigned to the same assignee as this application, now U.S. Pat. No.3,704,068 of Nov. 28, 1972) a microfiche defined by an emulsion filmcarried on one surface of a clear plastic sheet is positioned next to aplastic plate having discrete optically active surfaces, i.e., lenses.An apertured mask may be employed, the mask inhibiting overlapping ofadjacent information. The proturberances function as lenses (termedlensettes because of their small size) and are intended to be alignedwith optical bits of information on the microfiche emulsion, therebyprojecting and magnifying the bits. In such constructions it is ofparamount importance that the distance between the emulsion and thelensettes remain constant during all readout movements of the microficheand over all portions of its area. This is so because of the relativelysmall focal lenghts of the lensettes and the degree of magnificationinvolved. Thus, relatively small variations in the distance between theemulsion and lensettes cause large changes in the final, projected imageof the intelligence. If, for example, the viewing screen and microficheare 8 inches × 10 inches, then the distance between the emulsion andlensettes must not vary even as much as a mil over the 80 sq. inchesarea if satisfactory images of the intelligence are realized.

According to the practice of the instant invention, this criticality iseliminated by embossing or molding the microfiche to thereby definelensettes on and integral with the fiche itself. Thus, the emulsionwhich carries the information, and the clear plastic sheet (e.g., methylmethacrylate) which carries the emulsion, and the lensettes, all definea unitary structure. By this construction, movement of the microficherelative to projecting light sources (in order to read out theinformation) cannot result in variations of the distance between theemulsion and the projecting lensettes. This distance now becomes afunction only of the microfiche thickness, a quantity which may beaccurately controlled during manufacture of the microfiche.

In an embodiment, the apertured mask is replaced by opaque coatings onthe microfiche, between the lensettes.

IN THE DRAWINGS

FIG. 1 is a partial cross-sectional view of a prior art distributedoptics microfiche reader.

FIG. 2 is a view of a similar reader, but showing the novel microficheconstruction of this invention.

FIG. 3 is an enlarged view of a portion of FIG. 2.

FIGS. 4a and 4b are similar to FIG. 3, and illustrate an optimum shapeof individual micro-optical cells.

FIG. 5 is a view similar to FIG. 2, and illustrates an embodimentwherein interlensette surface is opaque.

FIG. 6 is a partial view, similar to FIG. 5, and illustrates anotherembodiment.

FIG. 7 is a view, similar to FIG. 6, and illustrates an embodimentwherein the micro-images reside on Petzval surfaces.

FIG. 8 is a view, similar to FIG. 2, illustrating an embodiment whereinthe micro-images carried by the fiche are illuminated for readout fromthe top or front.

FIG. 9 is a perspective view of an illuminating device, and its mannerof fabrication, used in the embodiment of FIG. 8.

FIG. 10 is a partial view of FIG. 9, at a later stage in formation.

FIG. 11 is a perspective view of the front illuminating arrangement ofFIG. 8.

FIG. 12 is a view along line 12--12 of FIG. 11.

FIG. 13 is a view along line 13--13 of FIG. 11.

FIG. 14 is a partial perspective view along line 14--14 of FIG. 8 andillustrates the ends of the light rods abutting channel ends in theviewing screen.

FIG. 15 is a view taken along section 15--15 of FIG. 8.

FIG. 16 is a front view, partially schematic, of a reader having a frontilluminated fiche.

FIGS. 17 and 17a are schematic views of a mode employing a grid of lightemitting diodes.

Referring now to FIG. 1 of the drawings, a prior art construction of amicroreader such as shown in the noted Waly patent is schematicallyillustrated. The numeral 10 denotes a viewing screen formed of, forexample, a translucent material. Septa 12 are positioned as indicatedand extend downwardly from the screen 10 to plate 14, the septa dividingthe entire surface of the screen 10 into small areas or cells. Thepurpose of the septa is to inhibit crosstalk, i.e., image overlapping.The numeral 14 denotes a lens plate having integral nodules orproturberances 15, each of which defines a projecting lens forprojecting onto the under surface of screen 10. The lens plate 14 may beformed of, for example, clear plastic having an index of refraction ofapproximately 1.5. The numeral 16 denotes a mask having spaced openingsor apertures 17 which are in alignment with the optical axes of thevarious lensettes 15. The numeral 18 denotes an emulsion, greatlyexaggerated in thickness for purposes of illustration, carried by aplate 20 of, for example, a clear plastic such as methyl methacrylate.The element 20 with its emulsion 18 is termed a microfiche. The numeral22 denotes a spacing or positioning plate which carries a plurality offiber optic light conducting pipes or tubes 24. The upper termini arealigned with the optic axes of the several lensettes 15. The light pipes24 are fed in a conventional manner to a suitable source ofillumination.

For purposes of illustration, micro images of the letters (bits) of theword OBJECT, in distributed or spaced form, are carried by the emulsion18. A second information set which might contain the words CAT IS isalso carried by the emulsion 18.

In operation, the microfiche 20 is inserted between the lens plate 14and the positioning plate 20 and the source of illumination (notillustrated) is energized. Light passes from the light pipes 24 throughthe transparent body of the microfiche, through the emulsion 18 whichcarries the intelligence. The several letters of the information OBJECTare thus projected through the apertures 17 of the mask 16 and passthrough lensettes 15. The projection thus appears in inverted form(because only a single lens has been used) on the viewing screen. Inorder to view the next segment, as for example the next page, ofinformation recorded on the microfiche 20, the microfiche is moved tothe left by an indexing mechanism, thereby aligning the letters (bits)of CAT IS with the openings 17. The letters of this second message willthen appear on the viewing screen 10, as in the first case.

Because of the relatively small focal lengths of the lensettes 15, it isimportant that the distance between the emulsion 18 and the lensettes 15vary by less than 1 mil over the entire surface of the fiche and duringall movements of the microfiche relative to the lens plate 14 and plate20 during the scanning or readout procedure. If the screen 10 isrelatively large, say 8 inches × 10 inches, then this would require thatall of the distances between the lensettes 15 and the emulsion 18 overthe entire 80 sq. inches vary by less than 1 mil. This is difficult torealize in practice and any variations in this critical distanceadversely affects the quality of the image on viewing screen 10.

Referring now to FIG. 2 of the drawings, the improvement of thisinvention is illustrated. Here, the same numerals represent the sameelements as in FIG. 1. It will be observed, however, that lens plate 14which carries the lensettes 15 is omitted. Instead, the microfiche 20itself is provided, on one surface, with a multiplicity of integrallensettes each denoted by the numeral 21. The emulsion 18 is placeddirectly against the termini of light pipes 24, and mask 16 placed ontop of microfiche 20. Again, for purposes of illustration the drawingsshow schematically a part of a message containing the word OBJECTcarried by the emulsion 18. Again, illumination of light pipes 24 causeslight to pass through the emulsion 18, illuminating the individualletters or bits of the message, the light rays then continuing throughthe microfiche striking the lens elements 21, and again being projectedon viewing screen 10.

The lens elements 21 are formed by embossing or molding the top surfaceof microfiche 20, the microfiche exhibiting over its entire top surfacea multiplicity of lens elements 21, much as in the manner of a streetpaved with cobblestones.

A comparison of FIGS. 1 and 2 readily illustrates the advantages of theinvention. For example, referring to FIG. 1, if the microfiche 20 moveseven slightly toward or away from the lens elements 15, the quality ofthe final image as viewed on screen 10 will suffer. Yet, such movementis entirely possible because of, among other things, the necessaryclearance between the top of plate 22 and the bottom of plate 14. Indistinction to this behavior, a consideration of FIG. 2 will show thatno matter how the microfiche 20 is moved, the distance between theemulsion 18 and the lens elements 21 will remain constant. This distancecorresponds to the thickness of the microfiche and is very easilycontrolled to a high degree of accuracy at its place of manufacture. Itwill be observed that each letter in the intelligence carried byemulsion 18 centers on the optic axis of each corresponding lens element21. This follows from the fact that the arrangement of FIG. 2 is used asa taking camera. The intelligence to be microfilmed is placed on thescreen 10 and photographed, so to speak, by the emulsion 18. During thisprocess, each of the septa 12 and each aperture 17 in mask 16 insuresthat only one letter of the intelligence on a screen 10 appears directlybelow each lens 21 on emulsion 18. Thus, there is always opticalalignment between the reduced letters or intelligence carried by theemulsion and their corresponding lens element 21. Further, if there is aslight inaccuracy in the embossing or molding process duringmanufacture, the error is undone in the viewing or readout because eachlensette acts as a camera in the taking process. Thus, lateralpositioning of each optical bit (letter) with respect to the optic axisof each lensette are no longer a critical factor.

FIG. 3 illustrates certain relations between the microfiche thickness,the lensette radii, and the magnification of the constructionillustrated at FIG. 2 of the drawings, the microfiche object carried bythe emulsion 18 being an arrow A and its projection on the viewingscreen by A'.

The following relations obtain in FIG. 3: ##EQU1## and the magnificationis: ##EQU2## where: u is the object distance

n is the index of refraction in the object space

v is the image distance

n' is the index of refraction in the image space

R is the radius of curvature of the refraction surface

m is the magnification

The following example will illustrate these relations, where m = 25 andn = 1.5 (e.g. plexiglass). For standard 7 mil film, u = 7 mils, m = 25,and n = 1.5. Then v = 117 mils and R = 2.25 mils. (Such small lensettes21 are perfectly feasible optically and very high quality resolution forthem has already been demonstrated by K. Peter; see PhysikalisheBlatter, Vol. 17, page 21, 1961.)

Assume the image of an individual letter on screen 10 to be a character100 mils in height and 100 mils wide. Therefore, the "object" in theemulsion 18 will be contained in an area 4 mils by 4 mils. Hence, thespacing s between the axes of adjacent lensettes is 4 mils.

The mask 16 with its aperture stops 17 plays an important role in theconstruction illustrated at FIG. 2. The mask 16 is stationary withrespect to screen 10, septa 12, and plate 22 which supports light pipes24. The size of the aperture 17 of the mask depends upon the optimum fnumber and is determined as follows:

The focal length f of a lens is given by the relation ##EQU3## Hence,for n' = 1.5 and n = 1 and R = 2.25 mils

    f = 3 × R = 6.75 mils

The optimum f number, denoted by f', should be 4, according to W. E.Rudge et al in their monograph regarding Fly's-Eye Lens Technique, etc.,described in I.B.M. Journal, page 146 et seq. for April, 1963. An fnumber f' greater than 4 means loss of paraxial resolution due torefraction, and f numbers around 3 or less yield loss of resolution dueto geometric abberations. ##EQU4##

Consider the case where the distance u is 7 mils, corresponding tomicrofiche thickness of 7 mils. Here, R = 2.25 mils and the focal lengthequals 6.75 mils. For optimum f of 4, the diameter of the mask openings17 should be: ##EQU5##

These relations are illustrated at FIGS. 4a and 4b of the drawings. Itis seen that the aperture openings 17 cover the central portion of thearea of each lensette 21 and that the information bits schematicallyindicated (A) contained in the emulsion 18 are larger than the openings17. The distance between apertures 17 is one-tenth inch and there wouldthus be, for this example, 25 lensettes 21 between the apertures. Theareas indicated by the dashed lines contain the stored bits and areclose-packed, as indicated, for maximum storage density.

In view of the extermely small distances between the micro images onemulsion 18, the small radius of curvature of lensettes 21, the smallmask openings 17, and the necessity of accurate alignment of the opticaxes of lensettes 21 with the openings 17, even the smallest departurefrom intended sizes and distances is quite significant. With, forexample, an 8 inches × 10 inches lensfiche, there are five millionapertures 17 in mask 16 and a corresponding five million lensettes 21,all of which must be properly aligned. (For an 8 inches × 10 incheslensfiche containing 80 × 10⁶ square mils, each 4 × 4 mil emulsion cellfor the microimages contains 16 square mils, there are 80 × 10⁶ /16 = 5× 10⁶ lensettes). The vertical distance from the mask openings 17 to themicro images on emulsion 18 is also important, otherwise overlapping(cross-talk) between the cells in emulsion 18 may occur. Thus the actualfabrication of the previously described embodiment which must satisfythe enumerated conditions is difficult to realize.

The embodiment of FIGS. 5, 6 and 7 substantially lessens the effects of(inherent) fabrication tolerances, in a manner now to be set forth.

Referring to FIG. 5, the numerals 18, 20 and 21 designate the sameelements as previously described. The lensettes 21 are now spaced fromeach other along the plane of the lensfiche and are depressed, lyingeach in a depression or cavity 50. The remaining areas of the top of thelensfiche, i.e., the interlensette area, are provided with an opaquecoating denoted by the numeral 51. The numeral 52 denotes a transparentplastic block which may be of methyl methacrylate, the top surface ofwhich may be coated with a light-diffusing film 54 adapted to serve as aviewing screen. The bottom surface 56 of block 52 is coated with anopaque substance, except for apertures 58, and may additionally becoated with an anti-friction material such as Teflon. Light pipes 24carried by plate 22 illuminate the micro images carried by emulsion 18for projection on viewing screen 54.

In operation, the lensfiche is moved (indexed) by sliding, andsuccessive groups of lensettes 21 are exposed to those termini of lightpipes 24 which are aligned with openings 58. The micro images carried bythe emulsion are optically projected upwardly through lensettes 21,block 52 and appear in magnified form on screen 54. If desired, septasuch as 60 may be molded into block 52 to inhibit overlapping of imageson the viewing screen. Two letters of a recorded information set inemulsion 18 commencing with OBJECT are schematically illustrated. Themicro image of the letter "O" is shown (necessarily out of scale due todrawing size limitations) on emulsion 18 and appears on screen 54greatly magnified. Similarly, the micro image of the next letter "B"appears on screen 54. The 4 × 4 mil cells in emulsion 18 which containthese two micro images are denoted, respectively, by the areasunderneath vincula 70 and 72.

In order to project the next information set on screen 54, the lensficheis moved to the left. For this second information set, commencing forexample with CAT IS, the first two letters "C" and "A" are illustratedas occupying adjacent 4 × 4 mil areas in emulsion 18 underneath vincula74 and 76, respectively. Magnified images of the letters "C" and "A"will now appear on screen 54 in the same places illustrated for letters"O" and "B". The micro images of letters "O" and "B" now are positionedbeneath opaque surface 56, laterally of opening 58, and are hence notprojected on the screen.

Each lensette 21 is vertically aligned with a 4 × 4 mil area on emulsion18, such areas being either square, or hexagonal (with 4 mil spacedcenters), or any similar configuration which yields a close-packed cellarrangement for maximum utilization of the area of emulsion 18. Eachaperture 58 corresponds in outline to the shape of the micro image cellsin emulsion 18. Thus, if the apertures 58 are hexagonal, the micro imagecells will be hexagonal.

The mask 16 and apertures 17 of the embodiment of FIG. 2 are replaced byopaque coatings 51 on the lensfiche and openings 58 on opaque coating56. The problem of accurate optical alignment of mask openings withlensettes is thereby overcome. The openings 58 are of a diameter equalto the inter-lensette spacing, e.g., 4 mils in the example given, andsmall variations in this diameter are not critical.

FIG. 6 is a partial view of another embodiment, identical with theembodiment of FIG. 5, except that the lower surface of block 52 isprovided with lens-defining curved surfaces 62. Such lenses 62 arepositioned within each aperture 58 and define, with lensettes 21, aprojection lens system which yields greater magnification than possiblewith lensettes 21 alone.

FIG. 7 illustrates an embodiment of the lensfiche itself. Here the lowersurface of the lensfiche is provided with integral nodules 70 on whichthe emulsion 18 is placed. The surface of each nodule is of a specialshape known as a Petzval surface. A Petzcal surface is one on which animage placed will yield maximum clarity and sharpness when projected.Each surface 70 is aligned with a corresponding lensette 21, and definesa microimage cell as in the previous embodiments. Such Petzval surfacesmay also be employed with the embodiment shown at FIG. 2.

While discrete information units or bits, such as the letters in OBJECTand CAT IS have been selected to illustrate the invention thus fardescribed, it will be understood that continuous forms of informationmay be also accommodated. Thus, photographs may also be first reducedand thence projected. Each scene on the viewing screen may be regardedas a macro scene, whether the same size as the original (a page of abook), smaller than the original (a mountain landscape) or larger thanthe original (enlargement of a microphotograph). Each macro scenecorresponds to a unique set, termed an information set, of micro imagesin the lensfiche emulsion. In turn, each unique information setcorresponds to a unique set of lensettes 21. Thus, referring to FIGS. 2and 5, one information set includes the micro images of the letters inthe word OBJECT, while another distinct and unique information setincludes the letters in the phrase CAT IS. As shown, a lensette isaligned and associated with a single micro image. The samecorrespondence holds in the case of continuous information. The variousinformation sets are interlaced in the sense of interlocked fingers andare also distinct as are the pieces of a jigsaw puzzle. The totality ofinformation sets recorded on the lensfiche forms a mosaic whoseindividual elements are the dispersed areas of the various informationsets.

The same advantages and mode of operation of the invention follow for aprojection lens array which requires lensettes 21 to be concave withrespect to the top surface of the lensfiche 20 instead of convex as hasbeen illustrated. Further, in lieu of proturberances (convex lensettes)or depressions (concave lensettes) optical anisotropys in the fiche maybe employed for the purpose of changing the direction of light rays.Accordingly, the phase "optically active surface" appearing in theclaims is intended to embrace these distinct yet equivalentconstructions.

The lensfiche is moved relative to the mask apertures, to successivelyexpose distinct information sets, by an indexing mechanism, notillustrated, and which forms no part of this invention. The informationsets and mask openings may be rectangularly arranged such as shown atFIG. 2 of the noted Waly application, and thus require both row andcolumn indexing motions. The information sets and mask openings may alsobe arranged in a skew manner, such as shown at FIGS. 4 and 5 of thenoted Waly patent, and thus require only column indexing.

From a consideration of FIGS. 2 and 5 of the drawings, it may be readilyvisualized that the same results are obtained with the microfichestationery with respect to the screen and the mask relatively movable.Thus, referring particularly to FIG. 2, by placing a light pipe 24underneath each microimage and fixing the microfiche relative to thescreen 10 and supporting plate 22, indexing movement of the mask 16 willexpose each set of microimages carried by emulsion 18 to an aperture 17,with attendant projection on the screen 10. With the FIG. 5construction, each lensette 21 may be provided with a correspondinglight pipe 24. The opaque coating 56 on the bottom of screen block 52 isreplaced with an opaque mask having apertures 58 of the same size asshown, the mask undergoing sliding (indexing) motion with respect to thestationary microfiche and screen and positioned between them. Again,each set of microimages carried by the microfiche is sequentiallyexposed through mask openings 52 for projection onto the viewing screen.The opaque coatings 51 (FIG. 5), as before, inhibit cross-talk(overlapping of projected images). However, the septa 12 of FIG. 2 and60 of FIG. 5 are omitted in the movable mask embodiment.

It will be noted that upon changes in dimensions of the lensfiche 20 dueto either temperature or humidity fluctuations, the optical registrybetween the emulsion-carried intelligence and the lensettes 21 will notbe disturbed. They will both suffer or undergo the same displacement.

An embodiment will now be described wherein the lensfiche is illuminatedfrom the top or front, in distinction to bottom or rear lighting as inthe previously described constructions. By reference to FIG. 5, forexample, a rear lighting mode requires both lensfiche surfaces to betransparent. Further, the location of the light pipes adds thickness tothe entire reader ensemble since they require space on the side of thelensfiche opposite the viewing screen.

FIG. 8 illustrates such a front lighting embodiment.

Referring now to FIG. 8, the numeral 82 represents one of a plurality oflight-pipe elements which lie in troughs in the bottom surface oftransparent plastic plate 52. The light-pipe 82 is preferably externallycoated so as to produce total internal reflection. Similarly, thesurface and end of the trough in which the light-pipe 82 is positionedmay be mirrored. As indicated by the arrows coming from the left in FIG.8, light passing down light-pipe 82 is reflected at the end of the tubeand into one of the lensettes 21. This light continues through fiche 20until striking the lower portion where the emulsion 18 is located. Aportion of the light is then reflected upwardly. Of all this lightreflected upwardly, a portion will define a light cone through theadjacent lensette 21. Thus, the micro-image immediately below thelensette through which the light cone passes, as indicated, is projectedonto the screen 54 of the plate 52.

In order to read or scan the next information set, i.e., the next stagefor example, the fiche 20 is indexed to the left so that the lensette 21associated with the illustrated light cone is now the lensette throughwhich the light from light pipe 82 passes to illuminate the nextadjacent micro-image on emulsion 18. As will presently be furtherexplained, each aperture 58 of transparent plate 52 has associatedtherewith an adjacent end of a light-pipe 82. The optic axis, asindicated, will remain the same while the fiche 20 is indexed tosuccessively read out the information.

FIG. 9 illustrates one step in fabricating the front or top illuminationembodiment shown at FIG. 8. Initially, a clear plastic such as methylmethacrylate may be coated with a substance having a different index ofrefraction so as to produce total internal reflection. Next, a set ofdies in the configuration illustrated at FIG. 9 is applied to the topand the bottom of a plane methyl methacrylate sheet. The dies beingpressed together, the result as indicated at FIG. 9 follows. That is tosay, the plastic sheet which was once plane on both surfaces is nowtransformed into a plastic sheet having a series of regular andlongitudinal indentations for the purpose of defining the equivalent ofindividual light-pipes. As the next step, the forward end, as viewed atFIG. 9, of the light-pipes 82 is cut as indicated to produce asaw-toothed configuration as partially indicated at FIG. 10. The ends ofthese forward light-pipes 82 are suitably beveled and coated with areflecting surface, if desired, so that when placed in troughs in thebottom of plate 52 light will be reflected downwardly, as indicated atFIG. 8. Again, referring to FIG. 9, the outer rearmost end of thelight-pipe ensemble is wrapped or curled about the indicated axis, itbeing recalled that the light-pipe ensemble is flexible. This results inthe roll 80 shown at FIG. 11, with the individual series of saw-toothedsets of light-pipes 82 placed in the indicated bottom of plate 52.

FIGS. 12 and 13 indicate the trough formation in the bottom of plate 52,and show that as the distance to the ends of the saw-teeth is increased,the number of individual light-pipes 14 which abut reflecting surfacesdecreases. FIG. 14 illustrates how the various ends of the individuallight-pipes 82 abut the ends of the troughs in plate 52.

Reference now to FIG. 15 will further illustrate the front or toplighting embodiment. The ends of the individual light pipes 82 aredenoted by the numerals 86, 88, 90 and 92. The adjacent lensettes 21,through which the reflected light passes upwardly for projection onscreen 54, are designated by numerals 94, 96. As indicated, thelensettes 21, corresponding to apertures 58, through which theprojections are made are spaced 100 mils apart, their being 25 4 × 4micro-image storage areas on the emulsion 18 between the apertures 58through which the projection proceeds.

FIG. 16 further illustrates a construction wherein top or front lightingis employed. FIG. 16 may be viewed as a further stage in theconstruction partially illustrated at FIG. 11. In FIG. 11, only half ofthe plate 52 is illustrated as provided with the illuminatinglight-pipes 82. In FIG. 16, both sides of the plate 82 are provided witha roll 80. As indicated at FIG. 16, the top ends of the two rolls 80 areilluminated as indicated, the top ends defining a plurality of parallellight-pipe ends arising through the process indicated by wrapping atFIG. 9.

Reference to FIGS. 17 and 17a illustrates still another embodiment,wherein motion of the microfiche is not necessary for readout. In lieuof light pipes illuminating the rear of the microfiche, a grid of lightemitting diodes (LED) may be employed, with one LED beneath eachlensette. The mask 56 and apertures 58 may then be omitted from theembodiment of FIG. 5, and a consideration of FIG. 5 shows that byplacing such a grid beneath a (stationary) microfiche 20, in lieu oflight pipes, each LED in the grid will illuminate a corresponding andunique microimage in emulsion 18 and associated lensette 21. Byenergizing different sets of LEDS in the grid, as indicated by theseveral switch positions, different sets of microimages may beilluminated for projection through the lensettes and onto the viewingscreen. By this substitution of LEDs for the light pipes, no movementbetween the microfiche and screen or between the (omitted) mask andmicrofiche is required for readout. FIG. 17a illustrates, schematically,a single LED of the grid.

In each of the described embodiments the actual scale has not been shownin all cases because of drawing size limitations. The same holds truefor the number of lensettes between several of the mask apertures. Insome cases angles have been greatly exaggerated for the purpose ofclarity.

I claim:
 1. A microfiche reader for projecting and viewing micro opticinformation, including,a. a viewing screen, b. an apertured mask spacedfrom said screen and parallel thereto, c. means for supporting amicrofiche having optically active elements, said microfiche beingparallel to said viewing screen and spaced therefrom, d. means toilluminate said microfiche and project micro images thereon through saidmask apertures and thence onto said viewing screen, e. means forpreventing overlapping of projected micro images on said screen, saidmeans defined by opaque septa positioned between said screen and saidapertured mask.
 2. The microfiche reader of claim 1 wherein said septadivide the space between said screen and said apertured mask into aplurality of cells, there being one such cell for each of said aperturesin the mask, said septa being normal to said screen.
 3. The micirofichereader of claim 1, including:a. a microfiche positioned adjacent saidapertured mask, b. said microfiche defined by a transparent sheetcarrying a plurality of optically active elements, each of which isadapted to function as a projecting lens, the bottom surface of saidmicrofiche carrying thereon micro images, each micro image opticallyaligned with one of said optically active elements, c. each aperture ofsaid mask being aligned with an optically active element of saidmicrofiche, d. the number of optically active elements being greaterthan the number of apertures in said mask.
 4. The microfiche reader ofclaim 1 wherein said (d) means is defined by a plurality ofside-by-side, touching light pipes adapted to project light through afiche having optically active surfaces, at said surfaces, thence throughsaid mask apertures onto the screen.
 5. The microfiche reader of claim 4wherein said (d) means is defined by a plurality of light pipes carriedby the lower portion of said viewing screen and having means at the endsthereof for projecting light downwardly and away from said viewingscreen, whereby light may be projected downwardly through one surface ofan optically active element of a microfiche to illuminate a micro imagecarried thereby on an opposite surface.
 6. The microfiche reader ofclaim 4 wherein each of the illuminating light output ends of said lightpipes project light onto a relfecting surface, to thereby illuminate asingle micro image of a microfiche, the reflecting surfaces being spacedfrom each other, said light pipes being supported by a plate.
 7. Amicrofiche reader including,a. a viewing screen, b. a support for amicrofiche, said support being generally parallel to said viewingscreen, c. means to illuminate a microfiche placed on said support, saidmeans defined by a matrix of light sources coupled to enablepredetermined sub-sets thereof to be energized, d. said light sourcesdefined by light emitting diodes, said diodes having switching circuitsto enable predetermined sub-sets only of said diodes to be energized,thereby permitting selected information sets carried by a microfiche tobe projected to a viewing screen, e. means for preventing overlapping ofprojected micro images on said screen, said means defined by opaquesepta positioned between said screen and said microfiche support.